What are the air pollution standards for particulate matter?

This Haze Guide bases on the US-Environmental Protection Agency (EPA) standard and index system for air pollutants which comprises Particulate Matter (PM10) and four other pollutants (NOx, SO2, CO and Ozone). In the following, only standards for particles are presented since other pollutants in the haze are of minor concern.

The US-National Air Quality Standards for particles (PM10) are 150 mg/m3 as the daily and 50 mg/m3 as the annual average. As a tool for easily assessing the daily air quality, EPA developed the Pollutant Standards Index (PSI). In this system, each pollutant is translated into an index value of which the highest value is reported as the current PSI. (Malaysia, for example, adopted a similar system, called Air Pollution Index (API)).

Table 1 shows the Pollution Standard Index (PSI) system for particles.

PM10 Concentration

PSI

Pollution Level

Air Quality Description

0 50 mg /m

<= 50

Standard

Good

51 150 mg /m

<= 100

Standard

Moderate

151 350 mg /m

<= 200

Alert

Unhealthful

351 - 420 mg /m

<= 300

Warning

Very Unhealthful

421 500 mg /m

<= 400

Emergency

Hazardous

501 600 mg /m

<= 500

Significant Harm

Hazardous

Table 1: Pollution Standard Index (PSI) system for particles (PM10) according to the US-EPA

Example: PM10-concentration between 351 and 420 mg /m is described as "very unhealthful" air quality ("warning").

How can I roughly assess the particle pollution level at my location?

As long as no reliable information on the current air pollution level is available, you can roughly assess the PM10-concentration at your location via the meteorological parameter visibility and relative humidity. This method bases on the fact that an increase of the particle concentration and humidity in the ambient air reduces visibility.

PM10
(mg /m3)

VISIBILITY in km

Rel. Humidity

10

5

4

3

2,5

2

1,5

1

0,7

0,5

0,4

0,3

0,2

0,1
50% 48 95 119 158 190 238 317 475 679 950 118 1584 2375 4751
60% 48 96 120 159 192 239 320 479 684 959 1198 1597 2395 4791
70% 49 97 121 161 194 242 323 484 691 968 1210 1614 2420 4838
80% 36 71 89 119 142 178 238 356 509 712 890 1186 1780 3559
85% 29 58 72 95 114 143 191 286 409 572 716 954 1430 2861
90% 21 42 52 70 85 105 140 211 301 420 526 701 1052 2103
95% 13 25 32 25 50 62 83 124 177 248 311 414 622 1244

Table 2: Correlation PM10-concentration (mg /m3) with visibility (km) and relative humidity (%) [Ref.: Hoyningen-Huene]

N.B.: This table reflects only statistical value, which can differ considerably from actual PM10 concentrations. However, this method is sufficient for rough estimates.

In order to obtain data on visibility and relative humidity, you can either consult the Internet at http://www.wunderground.com/global/ID.html. (Click at your location for detailed meteorological data). Or, please contact the closest meteorological station, which are generally located at the airport. Whereas the meteorological stations measure every hour, the meteorological data from the Internet are updated only 2 or 3 times a day. Please check regularly (morning, noon, evening) for updated data and collect them. It is advisable to assess the current PM10-concentration from several measurements each a day according to Table 2, to form their daily average and finally read off the air pollution level/PSI-index from Table 1.

Example: PSI for Medan, North-Sumatra on 27th October 1997:

Time

Visibility (rounded)

Rel. Humidity (rounded)

PM 10-Concentration (according to Table 2)

6 am

1.0 km

90 %

211 mg//m3

9 am

1.5 km

85 %

191 mg/ /m3

12 am

0.5 km

90 %

420 mg/ /m3

3 pm

0.5 km

95 %

284 mg/ /m3


The daily PM10-average is 277 mg/m3. This value corresponds to a PSI-Index of 101 to 200 (Table 1), meaning that the air pollution reached "unhealthful" conditions and "alert"-level.