# Presentation: 153668

## PM2.5 Forecasting in Texas

- Prepared by Bryan Lambeth
- Texas Commission on Environmental Quality
- February 2003

## Houston 2001 Nov 5

**Notes:**
View of downtown Houston – clear day

## Houston 2001 Nov 11

## Understanding the Problem

**Notes:**
Overview showing one year of daily averages at Houston Aldine C8 for 2001.

Most daily averages are in “Good” AQI range.
Numerous “Moderate” AQI measurements.
Only a few “Unhealthy for Sensitive Groups” measurements.

Continuous PM2.5 TEOM data shown in red.
Non-continuous shown in other colors.

## Understanding the Problem

**Notes:**
Closer view of daily averages for Nov 2001, showing peak episode for the year.

Data indicates high regional background levels during peak episode.
Large variation among area sites could be caused by local sources or by gradients in the background levels.
Also TEOM low bias accounts for part of the spread among area sites.

## Understanding the Problem

**Notes:**
Closer view of hourly averages for 2001 Nov 1-14.

Wind speeds were low for several days as PM2.5 increased.
Sudden increase in PM2.5 occurred mid-day on Nov 10.

Temperatures were mostly above 60 degF during the peak episode.

## Understanding the Problem

**Notes:**
Carbon monoxide helps to identify periods when local impacts are occurring.

Apparently there was a substantial local impact because of air stagnation.

## Understanding the Problem

**Notes:**
Speciated PM2.5 data from Houston Aldine C8 for 2001 Nov 12

## Understanding the Problem

- Houston 1997 Dec 18
- Local Stagnation - Winter

## Understanding the Problem

- Houston 1997 Sep 7
- Regional Haze with High Ozone

## Understanding the Problem

- Houston 1997 Jun 20
- Saharan Dust

## Types of High PM2.5 Events

- Regional dust storm (includes Saharan dust)
- Regional smoke (controlled and wild fires)
- Regional haze (stagnation – transport)
- Local stagnation (greatest local source impact)
- Local smoke (small fires near site)
- Local dust (dry weather – construction)

## Components of Forecast

- Regional background level- proximity to regional source areas - transport and dispersion- satellite imagery, visibility, and PM data
- Local contribution- proximity and intensity of local sources - wind speed and atmospheric stability- temperature and humidity- emissions inventory

## Regional Dust Storm

- 2001 April 10 5:15 PM MDT

- El Paso Area Peaks (g/m3 )
- PM2.5 1-Hour:  850 (C40)
-          24-Hour: **122** Unhealthy
- PM10 1-Hour: 11,652 (NM)
-          24-Hour:  **1,468** Hazardous

**Notes:**
Severe dust storm affecting El Paso 2001 April 10

Dust cloud extends from N Mexico across W Texas and much of E New Mexico

CAMS 40 in El Paso measured highest PM2.5 1-hour average of 850 ug/m3
 - highest in Texas in over 3 years of monitoring since Nov 1999

## Regional Dust – Long Range Transport

- 2001 June 22 5:15 PM CDT

**Notes:**
Saharan dust covering NW Caribbean on 2001 June 22

## Regional Dust – Long Range Transport

- 2001 June 25 5:15 PM CDT

- Peak 24-Hour PM2.5 (g/m3)
- Austin **32.2** Moderate (6/27)

**Notes:**
Saharan dust covering SW Gulf on 2001 June 5 – beginning to move into S Texas

Peak PM2.5 24-hour average of 32.2 ug/m3 recorded in Austin on 2001 Jun 27

## Regional Smoke

- 2002 May 2 5:15 PM CDT

- Peak 24-Hour PM2.5 (g/m3)
- Mission **33.7** Moderate

## Regional Smoke

- 2000 Sep 5 6:15 PM CDT

- Forest Fires

- Range Fires

- Marsh Fires

- Peak 24-Hour PM2.5 (g/m3)
- Houston **42.9** Unhealthy Sensitive
- Port Arthur **43.6** Unhealthy Sensitive

**Notes:**
Numerous fires with large smoke plumes during drought conditions
2000 Sep 5

## Regional Smoke and Dust

- Dust

- Smoke

- 2002 May 21 6:15 PM MDT

- El Paso Peaks (g/m3 )
- PM2.5 1-Hour:  72.9 (C12)
-          24-Hour: **21.1** Moderate
- PM10 1-Hour: 660 (C12)
-         24-Hour:  **144** Moderate

## Regional Haze

- 2002 Sep 10 6:15 PM CDT

**Notes:**
Large area of regional haze in Midwest US moving SW toward Texas

## Regional Haze

- 2002 Sep 14 6:15 PM CDT

- Peak 24-Hour PM2.5 (g/m3)
- Houston **57.5** Unhealthy Sensitive (9/13)

**Notes:**
Large area of regional haze covering E half of Texas

This is the same haze area that was in the Midwest US on Sep 10

The haze was largely transported into Texas from the NE

Air stagnation in Texas caused the haze to linger and increase in intensity

## Regional Haze

## Regional Haze

## Regional Haze

## Regional Haze - 2002 Sep 10

**Notes:**
Visibility contours at 3, 5, and 7 miles for 2002 Sep 10

## Regional Haze - 2002 Sep 11

**Notes:**
Visibility contours at 3, 5, and 7 miles for 2002 Sep 11

## Regional Haze - 2002 Sep 12

**Notes:**
Visibility contours at 3, 5, and 7 miles for 2002 Sep 12

## Regional Haze - 2002 Sep 13

**Notes:**
Visibility contours at 3, 5, and 7 miles for 2002 Sep 13

## Regional Haze - 2002 Sep 14

**Notes:**
Visibility contours at 3, 5, and 7 miles for 2002 Sep 14

## Local Smoke – Fireworks

- Peak PM2.5 (g/m3 )
- 1-Hour:  771 (C4)
- 24-Hour: **95** Unhealthy (C59)

**Notes:**
Heavy local smoke – primarily from fireworks 2002 Jan 01
At Corpus Christi, San Antonio and Houston

Highest 1-hour average of 771 ug/m3 at Corpus Christi C4
Highest 24-hour average of 95 ug/m3 at San Antonio C59

## Local Stagnation

- Photo
- 1/25

- Photo
- 1/29

## Local Stagnation – El Paso

- Relative Humidity 50%

- 2003 Jan 25 9:30 AM MST

## Local Stagnation – El Paso

- Relative Humidity 40%

- 2003 Jan 29 9:30 AM MST

## Regression Studies

- Multiple Linear Regression of PM2.5 versus- Yesterday PM2.5 - Wind Direction Resultant (WDR)- Wind Speed Average (WSA)- Average Temperature (Temp)
- Slightly better results obtained by substitutingPolynomial Regression results for each parameter into Multiple Linear Regression Model

## Dallas Linear Regression Model

- R2 = 0.4191

## Dallas Polynomial Regression Model

- R2 = 0.4622

## PM2.5 - Yesterday PM2.5

- R2 = 0.3192

## PM2.5 - Wind Direction

- R2 = 0.1032

## PM2.5 - Wind Speed

- R2 = 0.0734

## PM2.5 - Average Temperature

- R2 = 0.0225

## Houston Polynomial Regression Model

- R2 = 0.3709

## El Paso Polynomial Regression Model

- R2 = 0.3639

## TCEQ Web Pages

- Air Monitoring:_[http://www.tnrcc.state.tx.us/air/monops](http://www.tnrcc.state.tx.us/air/monops)_
- Air Pollution Events:_[www.tnrcc.state.tx.us/updated/air/monops/airpollevents/2003/sigevents_2003.html](http://www.tnrcc.state.tx.us/updated/air/monops/airpollevents/2003/sigevents_2003.html)__(analyses and descriptions of major air pollution events including high PM2.5 episodes)_
- Current PM2.5 Levels:_[www.tnrcc.state.tx.us/cgi-bin/monops/texas_pm25](http://www.tnrcc.state.tx.us/cgi-bin/monops/texas_pm25)_(map of Texas showing highest PM2.5 1-hour averages by metro area for last hour)