What is the current concentration of PM10 in Watertown, Massachusetts?

The current PM10 concentration at Watertown, Massachusetts is 9.574 μg/m3.

What is the current concentration of sulfur dioxide (SO2) in Watertown, Massachusetts?

The current sulfur dioxide (SO2) concentration at Watertown, Massachusetts is 0.528 ppb.

What is the current concentration of ozone (O3) in Watertown, Massachusetts?

The current ozone (O3) concentration at Watertown, Massachusetts is 34.244 ppm.

What is the current concentration of nitrogen dioxide (NO2) in Watertown, Massachusetts?

The current nitrogen dioxide (NO2) concentration at Watertown, Massachusetts is 4.138 ppb.

Watertown, Massachusetts live air quality index now

Q: What is the current concentration of PM2.5 in Watertown, Massachusetts?

The current PM2.5 concentration at Watertown, Massachusetts is 2.213 μg/m3.

Stay updated with real-time air quality in Watertown, Massachusetts featuring accurate data on AQI, PM_2.5, PM₁₀, O₃, NO₂, SO₂, and CO levels. Use our interactive map and detailed forecasts to monitor pollution trends, manage health risks, and plan your daily activities with confidence.

Live AQI (Air Quality Index)

Good

Watertown, Massachusetts

Last updated: ... (Local time)

Major air pollutants in Watertown, Massachusetts

Good

Fine

Moderate

Poor

Very poor

Hazardous

Particulate Matter_2.5 (PM_2.5)

2.21 μg/m³

12.1

35.5

55.5

250.5

500.5+

Particulate Matter₁₀ (PM₁₀)

9.57 μg/m³

155

255

425

605+

Ozone (O₃)

34.24 ppb

201

201+

Sulfur Dioxide (SO₂)

0.53 ppb

186

605

1005+

Nitrogen Dioxide (NO₂)

4.14 ppb

101

361

1250

2050+

Carbon Monoxide (CO)

0.27 ppm

4.5

9.5

12.5

230.5

50.5+

Pollen Level

Low

Watertown, Massachusetts

Get Live Pollen Counts

Watertown, Massachusetts

Scroll To Air Quality Map

Track live Watertown, Massachusetts air quality forecast and history

Time	AQI	PM_2.5	PM₁₀	O₃	SO₂	NO₂	CO
2026-05-19T12:00:00.000Z	66 \| moderate	16.757 \| fine	64.782 \| fine	33.614 \| good	0.681 \| good	10.544 \| good	0.314 \| good
2026-05-19T13:00:00.000Z	66 \| moderate	16.757 \| fine	64.782 \| fine	34.032 \| good	0.682 \| good	10.35 \| good	0.314 \| good
2026-05-19T14:00:00.000Z	66 \| moderate	17.445 \| fine	67.566 \| fine	41.209 \| good	0.733 \| good	8.375 \| good	0.291 \| good
2026-05-19T15:00:00.000Z	67 \| moderate	17.641 \| fine	68.691 \| fine	44.876 \| good	0.784 \| good	7.722 \| good	0.289 \| good
2026-05-19T16:00:00.000Z	67 \| moderate	17.706 \| fine	68.679 \| fine	52.226 \| good	0.883 \| good	8.039 \| good	0.283 \| good
2026-05-19T17:00:00.000Z	66 \| moderate	17.241 \| fine	67.77 \| fine	52.969 \| good	0.974 \| good	7.83 \| good	0.28 \| good
2026-05-19T18:00:00.000Z	66 \| moderate	16.906 \| fine	66.633 \| fine	54.948 \| good	0.976 \| good	7.038 \| good	0.28 \| good
2026-05-19T19:00:00.000Z	62 \| moderate	15.467 \| fine	60.576 \| fine	53.833 \| good	0.972 \| good	6.341 \| good	0.286 \| good
2026-05-19T20:00:00.000Z	64 \| moderate	15.969 \| fine	62.497 \| fine	58.921 \| fine	0.927 \| good	5.738 \| good	0.289 \| good
2026-05-19T21:00:00.000Z	64 \| moderate	15.969 \| fine	62.497 \| fine	54.185 \| good	0.927 \| good	5.688 \| good	0.289 \| good
2026-05-19T22:00:00.000Z	64 \| moderate	15.634 \| fine	61.849 \| fine	56.937 \| fine	0.741 \| good	4.92 \| good	0.2 \| good
2026-05-19T23:00:00.000Z	64 \| moderate	12.685 \| fine	51.025 \| good	59.244 \| fine	0.501 \| good	5.688 \| good	0.252 \| good
2026-05-20T00:00:00.000Z	54 \| moderate	9.802 \| good	38.919 \| good	56.394 \| fine	0.791 \| good	6.496 \| good	0.244 \| good
2026-05-20T01:00:00.000Z	54 \| moderate	10.714 \| good	42.288 \| good	54.481 \| good	0.979 \| good	8.856 \| good	0.336 \| good
2026-05-20T02:00:00.000Z	56 \| moderate	12.232 \| fine	48.237 \| good	51.128 \| good	0.592 \| good	7.678 \| good	0.333 \| good
2026-05-20T03:00:00.000Z	58 \| moderate	13.393 \| fine	52.93 \| good	42.972 \| good	0.591 \| good	6.433 \| good	0.242 \| good
2026-05-20T04:00:00.000Z	58 \| moderate	13.393 \| fine	52.93 \| good	42.599 \| good	0.591 \| good	6.45 \| good	0.239 \| good
2026-05-20T05:00:00.000Z	60 \| moderate	14.29 \| fine	55.895 \| fine	40.473 \| good	0.643 \| good	6.037 \| good	0.239 \| good
2026-05-20T06:00:00.000Z	62 \| moderate	15.289 \| fine	59.293 \| fine	37.236 \| good	0.546 \| good	4.721 \| good	0.195 \| good
2026-05-20T07:00:00.000Z	62 \| moderate	15.289 \| fine	59.293 \| fine	36.741 \| good	0.546 \| good	4.697 \| good	0.195 \| good
2026-05-20T08:00:00.000Z	62 \| moderate	14.703 \| fine	57.247 \| fine	32.963 \| good	0.577 \| good	4.145 \| good	0.192 \| good
2026-05-20T09:00:00.000Z	60 \| moderate	14.011 \| fine	53.996 \| good	28.002 \| good	0.532 \| good	6.473 \| good	0.234 \| good
2026-05-20T10:00:00.000Z	60 \| moderate	13.79 \| fine	53.087 \| good	27.599 \| good	0.629 \| good	6.623 \| good	0.234 \| good
2026-05-20T11:00:00.000Z	60 \| moderate	13.716 \| fine	53.019 \| good	27.147 \| good	0.633 \| good	7.976 \| good	0.239 \| good
2026-05-20T12:00:00.000Z	58 \| moderate	12.904 \| fine	50.349 \| good	28.792 \| good	0.679 \| good	8.889 \| good	0.242 \| good
2026-05-20T13:00:00.000Z	58 \| moderate	12.904 \| fine	50.349 \| good	24.683 \| good	0.68 \| good	9.168 \| good	0.242 \| good
2026-05-20T14:00:00.000Z	54 \| moderate	11.018 \| good	43.208 \| good	32.277 \| good	0.728 \| good	6.371 \| good	0.195 \| good
2026-05-20T15:00:00.000Z	54 \| moderate	10.587 \| good	42.1 \| good	36.821 \| good	0.727 \| good	6.388 \| good	0.197 \| good
2026-05-20T16:00:00.000Z	52 \| moderate	9.661 \| good	38.629 \| good	40.946 \| good	0.775 \| good	5.4 \| good	0.192 \| good
2026-05-20T17:00:00.000Z	49 \| good	9.378 \| good	37.424 \| good	41.751 \| good	0.823 \| good	5.194 \| good	0.189 \| good
2026-05-20T18:00:00.000Z	49 \| good	8.885 \| good	35.305 \| good	43.544 \| good	0.772 \| good	6.292 \| good	0.189 \| good
2026-05-20T19:00:00.000Z	49 \| good	8.885 \| good	35.305 \| good	48.15 \| good	0.773 \| good	6.362 \| good	0.186 \| good
2026-05-20T20:00:00.000Z	44 \| good	8.152 \| good	32.788 \| good	45.09 \| good	0.622 \| good	5.023 \| good	0.189 \| good
2026-05-20T21:00:00.000Z	44 \| good	8.152 \| good	32.788 \| good	46.704 \| good	0.623 \| good	4.98 \| good	0.189 \| good
2026-05-20T22:00:00.000Z	39 \| good	5.187 \| good	21.442 \| good	42.045 \| good	0.776 \| good	5.006 \| good	0.144 \| good
2026-05-20T23:00:00.000Z	40 \| good	5.187 \| good	21.442 \| good	42.512 \| good	0.778 \| good	5.141 \| good	0.144 \| good
2026-05-21T00:00:00.000Z	35 \| good	4.467 \| good	19.068 \| good	37.788 \| good	0.575 \| good	4.395 \| good	0.186 \| good
2026-05-21T01:00:00.000Z	37 \| good	3.939 \| good	16.681 \| good	40.383 \| good	0.575 \| good	3.94 \| good	0.186 \| good
2026-05-21T02:00:00.000Z	38 \| good	3.604 \| good	14.987 \| good	40.76 \| good	0.477 \| good	3.577 \| good	0.104 \| good
2026-05-21T03:00:00.000Z	39 \| good	3.154 \| good	12.906 \| good	41.782 \| good	0.535 \| good	3.686 \| good	0.123 \| good
2026-05-21T04:00:00.000Z	37 \| good	3.148 \| good	12.925 \| good	40.035 \| good	0.477 \| good	5.075 \| good	0.353 \| good
2026-05-21T05:00:00.000Z	36 \| good	3.148 \| good	12.925 \| good	39.428 \| good	0.319 \| good	5.068 \| good	0.353 \| good
2026-05-21T06:00:00.000Z	31 \| good	2.91 \| good	12.192 \| good	33.379 \| good	0.573 \| good	6.011 \| good	0.27 \| good
2026-05-21T07:00:00.000Z	31 \| good	2.91 \| good	12.192 \| good	34.117 \| good	0.573 \| good	5.879 \| good	0.27 \| good
2026-05-21T08:00:00.000Z	30 \| good	2.724 \| good	11.329 \| good	31.946 \| good	0.527 \| good	1.114 \| good	0.183 \| good
2026-05-21T09:00:00.000Z	31 \| good	2.457 \| good	10.426 \| good	32.794 \| good	0.528 \| good	2.695 \| good	0.266 \| good
2026-05-21T10:00:00.000Z	31 \| good	2.213 \| good	9.574 \| good	34.244 \| good	0.528 \| good	4.138 \| good	0.27 \| good
2026-05-21T11:00:00.000Z	28 \| good	1.986 \| good	8.625 \| good	30.351 \| good	0.57 \| good	5.652 \| good	0.27 \| good
2026-05-21T11:00:00.000Z	31 \| good	2.213 \| good	9.574 \| good	34.244 \| good	0.528 \| good	4.138 \| good	0.27 \| good
2026-05-21T12:00:00.000Z	22 \| good	3.936 \| good	17.213 \| good	21.617 \| good	0.427 \| good	3.836 \| good	0.125 \| good
2026-05-21T13:00:00.000Z	27 \| good	4.642 \| good	20.442 \| good	21.714 \| good	0.441 \| good	4.109 \| good	0.128 \| good
2026-05-21T14:00:00.000Z	27 \| good	4.913 \| good	21.041 \| good	23.888 \| good	0.445 \| good	3.968 \| good	0.128 \| good
2026-05-21T15:00:00.000Z	27 \| good	4.852 \| good	20.764 \| good	26.486 \| good	0.441 \| good	3.429 \| good	0.127 \| good
2026-05-21T16:00:00.000Z	27 \| good	4.951 \| good	21.505 \| good	27.315 \| good	0.434 \| good	3.094 \| good	0.127 \| good
2026-05-21T17:00:00.000Z	28 \| good	4.565 \| good	19.737 \| good	29.987 \| good	0.431 \| good	3.187 \| good	0.128 \| good
2026-05-21T18:00:00.000Z	32 \| good	4.222 \| good	18.473 \| good	35.101 \| good	0.431 \| good	3.258 \| good	0.128 \| good
2026-05-21T19:00:00.000Z	36 \| good	4.371 \| good	18.702 \| good	39.22 \| good	0.427 \| good	3.425 \| good	0.129 \| good
2026-05-21T20:00:00.000Z	37 \| good	4.138 \| good	18.382 \| good	39.941 \| good	0.414 \| good	3.542 \| good	0.128 \| good
2026-05-21T21:00:00.000Z	36 \| good	3.577 \| good	15.444 \| good	39.279 \| good	0.399 \| good	3.809 \| good	0.129 \| good
2026-05-21T22:00:00.000Z	33 \| good	1.042 \| good	3.931 \| good	35.65 \| good	0.378 \| good	4.144 \| good	0.13 \| good
2026-05-21T23:00:00.000Z	27 \| good	4.813 \| good	20.757 \| good	26.091 \| good	0.376 \| good	6.035 \| good	0.137 \| good
2026-05-22T00:00:00.000Z	38 \| good	6.626 \| good	29.152 \| good	20.931 \| good	0.422 \| good	11.332 \| good	0.16 \| good
2026-05-22T01:00:00.000Z	44 \| good	7.852 \| good	34.309 \| good	19.116 \| good	0.483 \| good	19.661 \| good	0.192 \| good
2026-05-22T02:00:00.000Z	49 \| good	8.616 \| good	37.717 \| good	19.43 \| good	0.476 \| good	18.285 \| good	0.181 \| good
2026-05-22T03:00:00.000Z	49 \| good	9.013 \| good	40.206 \| good	18.716 \| good	0.44 \| good	13.828 \| good	0.159 \| good
2026-05-22T04:00:00.000Z	44 \| good	8.001 \| good	34.892 \| good	20.143 \| good	0.412 \| good	9.651 \| good	0.142 \| good
2026-05-22T05:00:00.000Z	27 \| good	5.166 \| good	22.595 \| good	27.107 \| good	0.396 \| good	6.589 \| good	0.129 \| good
2026-05-22T06:00:00.000Z	27 \| good	4.831 \| good	20.864 \| good	27.464 \| good	0.39 \| good	4.879 \| good	0.123 \| good
2026-05-22T07:00:00.000Z	27 \| good	4.144 \| good	18.095 \| good	28.918 \| good	0.382 \| good	4.339 \| good	0.12 \| good
2026-05-22T08:00:00.000Z	27 \| good	4.502 \| good	19.384 \| good	26.541 \| good	0.376 \| good	4.635 \| good	0.122 \| good
2026-05-22T09:00:00.000Z	33 \| good	6.06 \| good	26.823 \| good	19 \| good	0.378 \| good	5.219 \| good	0.126 \| good
2026-05-22T10:00:00.000Z	38 \| good	6.684 \| good	29.772 \| good	25.118 \| good	0.384 \| good	5.877 \| good	0.131 \| good
2026-05-22T11:00:00.000Z	33 \| good	6.089 \| good	26.959 \| good	31.161 \| good	0.397 \| good	5.622 \| good	0.138 \| good
2026-05-22T12:00:00.000Z	32 \| good	5.179 \| good	22.634 \| good	35.049 \| good	0.405 \| good	3.987 \| good	0.132 \| good
2026-05-22T13:00:00.000Z	34 \| good	5.092 \| good	21.86 \| good	37.183 \| good	0.314 \| good	2.416 \| good	0.12 \| good
2026-05-22T14:00:00.000Z	35 \| good	4.875 \| good	20.979 \| good	37.663 \| good	0.297 \| good	1.957 \| good	0.117 \| good
2026-05-22T15:00:00.000Z	36 \| good	5.142 \| good	21.989 \| good	39.228 \| good	0.288 \| good	1.694 \| good	0.116 \| good
2026-05-22T16:00:00.000Z	37 \| good	5.222 \| good	22.809 \| good	40.142 \| good	0.279 \| good	1.575 \| good	0.115 \| good
2026-05-22T17:00:00.000Z	38 \| good	5.639 \| good	24 \| good	40.802 \| good	0.27 \| good	1.487 \| good	0.116 \| good
2026-05-22T18:00:00.000Z	40 \| good	5.985 \| good	26.747 \| good	43.229 \| good	0.262 \| good	1.476 \| good	0.116 \| good
2026-05-22T19:00:00.000Z	42 \| good	6.87 \| good	30.693 \| good	44.874 \| good	0.261 \| good	1.573 \| good	0.117 \| good
2026-05-22T20:00:00.000Z	40 \| good	7.02 \| good	30.845 \| good	42.955 \| good	0.267 \| good	1.821 \| good	0.118 \| good
2026-05-22T21:00:00.000Z	37 \| good	6.139 \| good	27.238 \| good	40.411 \| good	0.276 \| good	2.389 \| good	0.122 \| good
2026-05-22T22:00:00.000Z	33 \| good	3.881 \| good	17.092 \| good	35.989 \| good	0.286 \| good	3.487 \| good	0.127 \| good
2026-05-22T23:00:00.000Z	31 \| good	4.372 \| good	19.029 \| good	33.152 \| good	0.305 \| good	5.553 \| good	0.138 \| good
2026-05-23T00:00:00.000Z	31 \| good	4.888 \| good	21.35 \| good	34.164 \| good	0.34 \| good	8.868 \| good	0.157 \| good
2026-05-23T01:00:00.000Z	33 \| good	4.035 \| good	17.744 \| good	35.753 \| good	0.349 \| good	10.784 \| good	0.159 \| good
2026-05-23T02:00:00.000Z	33 \| good	3.899 \| good	16.959 \| good	35.804 \| good	0.35 \| good	12.298 \| good	0.161 \| good
2026-05-23T03:00:00.000Z	30 \| good	4.137 \| good	18.114 \| good	32.311 \| good	0.347 \| good	13.048 \| good	0.164 \| good
2026-05-23T04:00:00.000Z	28 \| good	3.983 \| good	17.145 \| good	29.874 \| good	0.327 \| good	12.434 \| good	0.165 \| good
2026-05-23T05:00:00.000Z	27 \| good	4.043 \| good	17.81 \| good	29.025 \| good	0.304 \| good	11.792 \| good	0.165 \| good
2026-05-23T06:00:00.000Z	54 \| moderate	10.648 \| good	12.353 \| good	20.08 \| good	0.298 \| good	12.371 \| good	0.167 \| good
2026-05-23T07:00:00.000Z	27 \| good	5.171 \| good	22.567 \| good	27.999 \| good	0.307 \| good	13.358 \| good	0.174 \| good
2026-05-23T08:00:00.000Z	33 \| good	5.659 \| good	24.618 \| good	27.698 \| good	0.328 \| good	14.786 \| good	0.182 \| good
2026-05-23T09:00:00.000Z	38 \| good	7.051 \| good	31.38 \| good	21.026 \| good	0.356 \| good	16.152 \| good	0.191 \| good
2026-05-23T10:00:00.000Z	27 \| good	5.449 \| good	23.652 \| good	25.52 \| good	0.388 \| good	17.795 \| good	0.2 \| good
2026-05-23T11:00:00.000Z	33 \| good	5.874 \| good	26.197 \| good	29.008 \| good	0.417 \| good	17.437 \| good	0.205 \| good

Watertown

Get reliable air quality data to drive your business

Watertown, Massachusetts air quality map: Track AQI near you

0.27ppm

How accurate is Massachusetts, USA air quality data?

Air quality data and pollutant measurements for Massachusetts, USA adhere to strict US EPA standards. The data is collected from multiple reliable sources, including satellites and ground-based monitoring stations. This data is further analyzed and enhanced using machine learning and advanced algorithms that factor in elements such as traffic and population density, ensuring accurate and reliable results.

Source: Ambee Data Sources

Air quality levels in US

Check live rankings of places in the USA affected by air pollution.

View Polluted Cities

Check live rankings of places in the USA with the cleanest air.

View Clean Cities

Frequently asked questions

How often is the air quality data for Watertown, Massachusetts updated?

The air quality for Watertown, Massachusetts is updated every hour.

When was the worst air quality at Watertown, Massachusetts in the last 24 hrs?

The worst air quality in Watertown, Massachusetts in the last 24 hours was observed at 11:00:00 on 2026-05-20.

When was the best air quality at Watertown, Massachusetts in the last 24 hrs?

In the last 24 hrs, the best air quality in Watertown, Massachusetts was observed at 08:00:00 on 2026-05-21.

What is the current air quality in Watertown, Massachusetts?

The current air quality in Watertown, Massachusetts is 31, categorized as Good based on real-time data.

What pollutant is the most common in Watertown, Massachusetts?

The most common pollutant in Watertown, Massachusetts is O3.

What should I do if the air quality in Watertown, Massachusetts is poor?

If the air quality in Watertown, Massachusetts is poor, consider staying indoors and wearing a mask to protect yourself.

What is the current concentration of PM_2.5 in Watertown, Massachusetts?

The current PM_2.5 concentration at Watertown, Massachusetts is 2.213 μg/m³.

What is the current concentration of PM₁₀ in Watertown, Massachusetts?

The current PM₁₀ concentration at Watertown, Massachusetts is 9.574 μg/m³.

What is the current concentration of carbon monoxide (CO) in Watertown, Massachusetts?

The current carbon monoxide (CO) concentration at Watertown, Massachusetts is 0.27 ppm.

What is the current concentration of sulfur dioxide (SO₂) in Watertown, Massachusetts?

The current sulfur dioxide (SO₂) concentration at Watertown, Massachusetts is 0.528 ppb.

What is the current concentration of ozone (O₃) in Watertown, Massachusetts?

The current ozone (O₃) concentration at Watertown, Massachusetts is 34.244 ppm.

What is the current concentration of nitrogen dioxide (NO₂) in Watertown, Massachusetts?

The current nitrogen dioxide (NO₂) concentration at Watertown, Massachusetts is 4.138 ppb.

Certified

APIs

Refund Policy

Historical Climate Data

Terms & Conditions

Refund Policy

Terms & Conditions

Time	AQI	PM_2.5	PM₁₀	O₃	SO₂	NO₂	CO
2026-05-19T12:00:00.000Z	66 \| moderate	16.757 \| fine	64.782 \| fine	33.614 \| good	0.681 \| good	10.544 \| good	0.314 \| good
2026-05-19T13:00:00.000Z	66 \| moderate	16.757 \| fine	64.782 \| fine	34.032 \| good	0.682 \| good	10.35 \| good	0.314 \| good
2026-05-19T14:00:00.000Z	66 \| moderate	17.445 \| fine	67.566 \| fine	41.209 \| good	0.733 \| good	8.375 \| good	0.291 \| good
2026-05-19T15:00:00.000Z	67 \| moderate	17.641 \| fine	68.691 \| fine	44.876 \| good	0.784 \| good	7.722 \| good	0.289 \| good
2026-05-19T16:00:00.000Z	67 \| moderate	17.706 \| fine	68.679 \| fine	52.226 \| good	0.883 \| good	8.039 \| good	0.283 \| good
2026-05-19T17:00:00.000Z	66 \| moderate	17.241 \| fine	67.77 \| fine	52.969 \| good	0.974 \| good	7.83 \| good	0.28 \| good
2026-05-19T18:00:00.000Z	66 \| moderate	16.906 \| fine	66.633 \| fine	54.948 \| good	0.976 \| good	7.038 \| good	0.28 \| good
2026-05-19T19:00:00.000Z	62 \| moderate	15.467 \| fine	60.576 \| fine	53.833 \| good	0.972 \| good	6.341 \| good	0.286 \| good
2026-05-19T20:00:00.000Z	64 \| moderate	15.969 \| fine	62.497 \| fine	58.921 \| fine	0.927 \| good	5.738 \| good	0.289 \| good
2026-05-19T21:00:00.000Z	64 \| moderate	15.969 \| fine	62.497 \| fine	54.185 \| good	0.927 \| good	5.688 \| good	0.289 \| good
2026-05-19T22:00:00.000Z	64 \| moderate	15.634 \| fine	61.849 \| fine	56.937 \| fine	0.741 \| good	4.92 \| good	0.2 \| good
2026-05-19T23:00:00.000Z	64 \| moderate	12.685 \| fine	51.025 \| good	59.244 \| fine	0.501 \| good	5.688 \| good	0.252 \| good
2026-05-20T00:00:00.000Z	54 \| moderate	9.802 \| good	38.919 \| good	56.394 \| fine	0.791 \| good	6.496 \| good	0.244 \| good
2026-05-20T01:00:00.000Z	54 \| moderate	10.714 \| good	42.288 \| good	54.481 \| good	0.979 \| good	8.856 \| good	0.336 \| good
2026-05-20T02:00:00.000Z	56 \| moderate	12.232 \| fine	48.237 \| good	51.128 \| good	0.592 \| good	7.678 \| good	0.333 \| good
2026-05-20T03:00:00.000Z	58 \| moderate	13.393 \| fine	52.93 \| good	42.972 \| good	0.591 \| good	6.433 \| good	0.242 \| good
2026-05-20T04:00:00.000Z	58 \| moderate	13.393 \| fine	52.93 \| good	42.599 \| good	0.591 \| good	6.45 \| good	0.239 \| good
2026-05-20T05:00:00.000Z	60 \| moderate	14.29 \| fine	55.895 \| fine	40.473 \| good	0.643 \| good	6.037 \| good	0.239 \| good
2026-05-20T06:00:00.000Z	62 \| moderate	15.289 \| fine	59.293 \| fine	37.236 \| good	0.546 \| good	4.721 \| good	0.195 \| good
2026-05-20T07:00:00.000Z	62 \| moderate	15.289 \| fine	59.293 \| fine	36.741 \| good	0.546 \| good	4.697 \| good	0.195 \| good
2026-05-20T08:00:00.000Z	62 \| moderate	14.703 \| fine	57.247 \| fine	32.963 \| good	0.577 \| good	4.145 \| good	0.192 \| good
2026-05-20T09:00:00.000Z	60 \| moderate	14.011 \| fine	53.996 \| good	28.002 \| good	0.532 \| good	6.473 \| good	0.234 \| good
2026-05-20T10:00:00.000Z	60 \| moderate	13.79 \| fine	53.087 \| good	27.599 \| good	0.629 \| good	6.623 \| good	0.234 \| good
2026-05-20T11:00:00.000Z	60 \| moderate	13.716 \| fine	53.019 \| good	27.147 \| good	0.633 \| good	7.976 \| good	0.239 \| good
2026-05-20T12:00:00.000Z	58 \| moderate	12.904 \| fine	50.349 \| good	28.792 \| good	0.679 \| good	8.889 \| good	0.242 \| good
2026-05-20T13:00:00.000Z	58 \| moderate	12.904 \| fine	50.349 \| good	24.683 \| good	0.68 \| good	9.168 \| good	0.242 \| good
2026-05-20T14:00:00.000Z	54 \| moderate	11.018 \| good	43.208 \| good	32.277 \| good	0.728 \| good	6.371 \| good	0.195 \| good
2026-05-20T15:00:00.000Z	54 \| moderate	10.587 \| good	42.1 \| good	36.821 \| good	0.727 \| good	6.388 \| good	0.197 \| good
2026-05-20T16:00:00.000Z	52 \| moderate	9.661 \| good	38.629 \| good	40.946 \| good	0.775 \| good	5.4 \| good	0.192 \| good
2026-05-20T17:00:00.000Z	49 \| good	9.378 \| good	37.424 \| good	41.751 \| good	0.823 \| good	5.194 \| good	0.189 \| good
2026-05-20T18:00:00.000Z	49 \| good	8.885 \| good	35.305 \| good	43.544 \| good	0.772 \| good	6.292 \| good	0.189 \| good
2026-05-20T19:00:00.000Z	49 \| good	8.885 \| good	35.305 \| good	48.15 \| good	0.773 \| good	6.362 \| good	0.186 \| good
2026-05-20T20:00:00.000Z	44 \| good	8.152 \| good	32.788 \| good	45.09 \| good	0.622 \| good	5.023 \| good	0.189 \| good
2026-05-20T21:00:00.000Z	44 \| good	8.152 \| good	32.788 \| good	46.704 \| good	0.623 \| good	4.98 \| good	0.189 \| good
2026-05-20T22:00:00.000Z	39 \| good	5.187 \| good	21.442 \| good	42.045 \| good	0.776 \| good	5.006 \| good	0.144 \| good
2026-05-20T23:00:00.000Z	40 \| good	5.187 \| good	21.442 \| good	42.512 \| good	0.778 \| good	5.141 \| good	0.144 \| good
2026-05-21T00:00:00.000Z	35 \| good	4.467 \| good	19.068 \| good	37.788 \| good	0.575 \| good	4.395 \| good	0.186 \| good
2026-05-21T01:00:00.000Z	37 \| good	3.939 \| good	16.681 \| good	40.383 \| good	0.575 \| good	3.94 \| good	0.186 \| good
2026-05-21T02:00:00.000Z	38 \| good	3.604 \| good	14.987 \| good	40.76 \| good	0.477 \| good	3.577 \| good	0.104 \| good
2026-05-21T03:00:00.000Z	39 \| good	3.154 \| good	12.906 \| good	41.782 \| good	0.535 \| good	3.686 \| good	0.123 \| good
2026-05-21T04:00:00.000Z	37 \| good	3.148 \| good	12.925 \| good	40.035 \| good	0.477 \| good	5.075 \| good	0.353 \| good
2026-05-21T05:00:00.000Z	36 \| good	3.148 \| good	12.925 \| good	39.428 \| good	0.319 \| good	5.068 \| good	0.353 \| good
2026-05-21T06:00:00.000Z	31 \| good	2.91 \| good	12.192 \| good	33.379 \| good	0.573 \| good	6.011 \| good	0.27 \| good
2026-05-21T07:00:00.000Z	31 \| good	2.91 \| good	12.192 \| good	34.117 \| good	0.573 \| good	5.879 \| good	0.27 \| good
2026-05-21T08:00:00.000Z	30 \| good	2.724 \| good	11.329 \| good	31.946 \| good	0.527 \| good	1.114 \| good	0.183 \| good
2026-05-21T09:00:00.000Z	31 \| good	2.457 \| good	10.426 \| good	32.794 \| good	0.528 \| good	2.695 \| good	0.266 \| good
2026-05-21T10:00:00.000Z	31 \| good	2.213 \| good	9.574 \| good	34.244 \| good	0.528 \| good	4.138 \| good	0.27 \| good
2026-05-21T11:00:00.000Z	28 \| good	1.986 \| good	8.625 \| good	30.351 \| good	0.57 \| good	5.652 \| good	0.27 \| good
2026-05-21T11:00:00.000Z	31 \| good	2.213 \| good	9.574 \| good	34.244 \| good	0.528 \| good	4.138 \| good	0.27 \| good
2026-05-21T12:00:00.000Z	22 \| good	3.936 \| good	17.213 \| good	21.617 \| good	0.427 \| good	3.836 \| good	0.125 \| good
2026-05-21T13:00:00.000Z	27 \| good	4.642 \| good	20.442 \| good	21.714 \| good	0.441 \| good	4.109 \| good	0.128 \| good
2026-05-21T14:00:00.000Z	27 \| good	4.913 \| good	21.041 \| good	23.888 \| good	0.445 \| good	3.968 \| good	0.128 \| good
2026-05-21T15:00:00.000Z	27 \| good	4.852 \| good	20.764 \| good	26.486 \| good	0.441 \| good	3.429 \| good	0.127 \| good
2026-05-21T16:00:00.000Z	27 \| good	4.951 \| good	21.505 \| good	27.315 \| good	0.434 \| good	3.094 \| good	0.127 \| good
2026-05-21T17:00:00.000Z	28 \| good	4.565 \| good	19.737 \| good	29.987 \| good	0.431 \| good	3.187 \| good	0.128 \| good
2026-05-21T18:00:00.000Z	32 \| good	4.222 \| good	18.473 \| good	35.101 \| good	0.431 \| good	3.258 \| good	0.128 \| good
2026-05-21T19:00:00.000Z	36 \| good	4.371 \| good	18.702 \| good	39.22 \| good	0.427 \| good	3.425 \| good	0.129 \| good
2026-05-21T20:00:00.000Z	37 \| good	4.138 \| good	18.382 \| good	39.941 \| good	0.414 \| good	3.542 \| good	0.128 \| good
2026-05-21T21:00:00.000Z	36 \| good	3.577 \| good	15.444 \| good	39.279 \| good	0.399 \| good	3.809 \| good	0.129 \| good
2026-05-21T22:00:00.000Z	33 \| good	1.042 \| good	3.931 \| good	35.65 \| good	0.378 \| good	4.144 \| good	0.13 \| good
2026-05-21T23:00:00.000Z	27 \| good	4.813 \| good	20.757 \| good	26.091 \| good	0.376 \| good	6.035 \| good	0.137 \| good
2026-05-22T00:00:00.000Z	38 \| good	6.626 \| good	29.152 \| good	20.931 \| good	0.422 \| good	11.332 \| good	0.16 \| good
2026-05-22T01:00:00.000Z	44 \| good	7.852 \| good	34.309 \| good	19.116 \| good	0.483 \| good	19.661 \| good	0.192 \| good
2026-05-22T02:00:00.000Z	49 \| good	8.616 \| good	37.717 \| good	19.43 \| good	0.476 \| good	18.285 \| good	0.181 \| good
2026-05-22T03:00:00.000Z	49 \| good	9.013 \| good	40.206 \| good	18.716 \| good	0.44 \| good	13.828 \| good	0.159 \| good
2026-05-22T04:00:00.000Z	44 \| good	8.001 \| good	34.892 \| good	20.143 \| good	0.412 \| good	9.651 \| good	0.142 \| good
2026-05-22T05:00:00.000Z	27 \| good	5.166 \| good	22.595 \| good	27.107 \| good	0.396 \| good	6.589 \| good	0.129 \| good
2026-05-22T06:00:00.000Z	27 \| good	4.831 \| good	20.864 \| good	27.464 \| good	0.39 \| good	4.879 \| good	0.123 \| good
2026-05-22T07:00:00.000Z	27 \| good	4.144 \| good	18.095 \| good	28.918 \| good	0.382 \| good	4.339 \| good	0.12 \| good
2026-05-22T08:00:00.000Z	27 \| good	4.502 \| good	19.384 \| good	26.541 \| good	0.376 \| good	4.635 \| good	0.122 \| good
2026-05-22T09:00:00.000Z	33 \| good	6.06 \| good	26.823 \| good	19 \| good	0.378 \| good	5.219 \| good	0.126 \| good
2026-05-22T10:00:00.000Z	38 \| good	6.684 \| good	29.772 \| good	25.118 \| good	0.384 \| good	5.877 \| good	0.131 \| good
2026-05-22T11:00:00.000Z	33 \| good	6.089 \| good	26.959 \| good	31.161 \| good	0.397 \| good	5.622 \| good	0.138 \| good
2026-05-22T12:00:00.000Z	32 \| good	5.179 \| good	22.634 \| good	35.049 \| good	0.405 \| good	3.987 \| good	0.132 \| good
2026-05-22T13:00:00.000Z	34 \| good	5.092 \| good	21.86 \| good	37.183 \| good	0.314 \| good	2.416 \| good	0.12 \| good
2026-05-22T14:00:00.000Z	35 \| good	4.875 \| good	20.979 \| good	37.663 \| good	0.297 \| good	1.957 \| good	0.117 \| good
2026-05-22T15:00:00.000Z	36 \| good	5.142 \| good	21.989 \| good	39.228 \| good	0.288 \| good	1.694 \| good	0.116 \| good
2026-05-22T16:00:00.000Z	37 \| good	5.222 \| good	22.809 \| good	40.142 \| good	0.279 \| good	1.575 \| good	0.115 \| good
2026-05-22T17:00:00.000Z	38 \| good	5.639 \| good	24 \| good	40.802 \| good	0.27 \| good	1.487 \| good	0.116 \| good
2026-05-22T18:00:00.000Z	40 \| good	5.985 \| good	26.747 \| good	43.229 \| good	0.262 \| good	1.476 \| good	0.116 \| good
2026-05-22T19:00:00.000Z	42 \| good	6.87 \| good	30.693 \| good	44.874 \| good	0.261 \| good	1.573 \| good	0.117 \| good
2026-05-22T20:00:00.000Z	40 \| good	7.02 \| good	30.845 \| good	42.955 \| good	0.267 \| good	1.821 \| good	0.118 \| good
2026-05-22T21:00:00.000Z	37 \| good	6.139 \| good	27.238 \| good	40.411 \| good	0.276 \| good	2.389 \| good	0.122 \| good
2026-05-22T22:00:00.000Z	33 \| good	3.881 \| good	17.092 \| good	35.989 \| good	0.286 \| good	3.487 \| good	0.127 \| good
2026-05-22T23:00:00.000Z	31 \| good	4.372 \| good	19.029 \| good	33.152 \| good	0.305 \| good	5.553 \| good	0.138 \| good
2026-05-23T00:00:00.000Z	31 \| good	4.888 \| good	21.35 \| good	34.164 \| good	0.34 \| good	8.868 \| good	0.157 \| good
2026-05-23T01:00:00.000Z	33 \| good	4.035 \| good	17.744 \| good	35.753 \| good	0.349 \| good	10.784 \| good	0.159 \| good
2026-05-23T02:00:00.000Z	33 \| good	3.899 \| good	16.959 \| good	35.804 \| good	0.35 \| good	12.298 \| good	0.161 \| good
2026-05-23T03:00:00.000Z	30 \| good	4.137 \| good	18.114 \| good	32.311 \| good	0.347 \| good	13.048 \| good	0.164 \| good
2026-05-23T04:00:00.000Z	28 \| good	3.983 \| good	17.145 \| good	29.874 \| good	0.327 \| good	12.434 \| good	0.165 \| good
2026-05-23T05:00:00.000Z	27 \| good	4.043 \| good	17.81 \| good	29.025 \| good	0.304 \| good	11.792 \| good	0.165 \| good
2026-05-23T06:00:00.000Z	54 \| moderate	10.648 \| good	12.353 \| good	20.08 \| good	0.298 \| good	12.371 \| good	0.167 \| good
2026-05-23T07:00:00.000Z	27 \| good	5.171 \| good	22.567 \| good	27.999 \| good	0.307 \| good	13.358 \| good	0.174 \| good
2026-05-23T08:00:00.000Z	33 \| good	5.659 \| good	24.618 \| good	27.698 \| good	0.328 \| good	14.786 \| good	0.182 \| good
2026-05-23T09:00:00.000Z	38 \| good	7.051 \| good	31.38 \| good	21.026 \| good	0.356 \| good	16.152 \| good	0.191 \| good
2026-05-23T10:00:00.000Z	27 \| good	5.449 \| good	23.652 \| good	25.52 \| good	0.388 \| good	17.795 \| good	0.2 \| good
2026-05-23T11:00:00.000Z	33 \| good	5.874 \| good	26.197 \| good	29.008 \| good	0.417 \| good	17.437 \| good	0.205 \| good

Watertown, Massachusetts live air quality index now

Major air pollutants in Watertown, Massachusetts

Particulate Matter2.5 (PM2.5)

Particulate Matter10 (PM10)

Ozone (O3)

Sulfur Dioxide (SO2)

Nitrogen Dioxide (NO2)

Carbon Monoxide (CO)

Track live Watertown, Massachusetts air quality forecast and history

Get reliable air quality data to drive your business

Watertown, Massachusetts air quality map: Track AQI near you

Air quality in nearby cities

Belmont, Massachusetts

Newton, Massachusetts

Waltham, Massachusetts

Arlington, Massachusetts

Cambridge, Massachusetts

Brookline, Massachusetts

How accurate is Massachusetts, USA air quality data?

Air quality levels in US

Frequently asked questions

How often is the air quality data for Watertown, Massachusetts updated?

When was the worst air quality at Watertown, Massachusetts in the last 24 hrs?

When was the best air quality at Watertown, Massachusetts in the last 24 hrs?

What is the current air quality in Watertown, Massachusetts?

What pollutant is the most common in Watertown, Massachusetts?

What should I do if the air quality in Watertown, Massachusetts is poor?

What is the current concentration of PM2.5 in Watertown, Massachusetts?

What is the current concentration of PM10 in Watertown, Massachusetts?

What is the current concentration of carbon monoxide (CO) in Watertown, Massachusetts?

What is the current concentration of sulfur dioxide (SO2) in Watertown, Massachusetts?

What is the current concentration of ozone (O3) in Watertown, Massachusetts?

What is the current concentration of nitrogen dioxide (NO2) in Watertown, Massachusetts?

Particulate Matter_2.5 (PM_2.5)

Particulate Matter₁₀ (PM₁₀)

Ozone (O₃)

Sulfur Dioxide (SO₂)

Nitrogen Dioxide (NO₂)

What is the current concentration of PM_2.5 in Watertown, Massachusetts?

What is the current concentration of PM₁₀ in Watertown, Massachusetts?

What is the current concentration of sulfur dioxide (SO₂) in Watertown, Massachusetts?

What is the current concentration of ozone (O₃) in Watertown, Massachusetts?

What is the current concentration of nitrogen dioxide (NO₂) in Watertown, Massachusetts?