Department of the Environment

Near Road NO2 Monitoring Update

MWAQC Technical Advisory Committee

January 10, 2012

Background NO2 NAAQS revised 1/22/2010

1-hour level set at 100 ppb

Monitoring required in urban area near major roadways where maximum concentrations are expected by Jan. 1, 2013

One near road monitor for areas with population > 300,000, additional monitor for areas with population > 2.5 million

Two monitors required for the DC/MD/VA CBSA and two monitors in the Baltimore CBSA

Build and Hold Plan In response to concerns raised by NACAA and

CASAC over the expeditious deployment schedule and resource/budgetary issues facing the States and EPA. EPA has developed the Build and Hold plan

Initial deployment of near road monitors now limited to areas with population > 1 million (subset of original requirements), one monitor per area.

Monitors to be deployed over two years (2013 and 2014)

Goal is to establish a sufficient base of monitors across the country so ambient concentrations can be assessed before deciding on whether to implement the full network

Build and Hold Plan

Build and Hold now means one monitor in the DC/MD/VA CBSA and one monitor in the Baltimore CBSA, both by Jan. 1, 2013

No formal revision to the existing monitoring requirements at this time

EPA and States left vulnerable to legal action

Site selection for Pilot studyNO2 near-road rule

“EPA proposed that the near road monitoring stations shall be selected by ranking all road segments within a CBSA by AADT (Annual Average Daily Traffic) … where maximum hourly NO2 concentrations are expected to be highest and siting criteria can be met. …. (other factors to consider) include vehicle fleet mix, roadway design, congestion patterns, terrain, and meteorology.”

The NO2 Technical Assistance Document developed a metric, the Fleet Equivalent (FE) AADT, to account for fleet mix and traffic counts FE-AADT = (AADT – HD) + HD*10 HD = heavy duty counts Factor of 10 is national average ratio of heavy duty NOx emissions / light duty NOx

emissions

Below are the top 20 AADT and FE-AADT segments in the Baltimore CBSA and population densities.

Top 20 AADT Top 20 FE- AADT

Comparing AADT to FE-AADT rank

STATION DEAADT rank

FE AADT rank AADT HD FE AADT

IS95-.50 MI N OF MD216 13 1 186750 29507 452309IS95-.50 MI S OF MD216 15 2 186040 28278 440543IS95-.40 MI N OF MD100 7 3 192100 26702 432417IS95-.70 MI S OF MD175 12 4 187920 26873 429773IS695-.40 MI N OF US1 (ARBUTUS) 5 5 192702 25244 419898IS695-.20 MI N OF MD144 8 6 191912 23029 399177IS95-.40 MI S OF WASHINGTON BLVD 24 7 173360 24964 398035IS95-.30 MI N OF WASHINGTON BLVD 25 8 173000 24739 395651IS83-.30 MI E OF JOPPA RD (ATR0031) 2 9 210790 20447 394810IS695-.50 MI N OF MD122 3 10 203902 21206 394754IS695-.20 MI N OF MD372 6 11 192302 22307 393065IS695-.30 MI N OF IS795 11 12 188352 21472 381601IS95-.50 MI S OF MD24 36 13 146750 25975 380523IS695-.20 MI S OF US1 (ARBUTUS) 21 14 177562 22373 378917IS95-.50 MI N OF MD43 29 15 160880 23488 372276IS695-.30 MI E OF MD140 14 16 186582 19778 364581IS 95 South of MD 103 4 17 193331 18753 362109IS695-.30 MI E OF STEVENSON RD 16 18 185822 19325 359751IS95-.20 MI N OF MD24 56 19 121100 26400 358698IS695-.50 MI S OF IS70 10 20 188860 17753 348636

Sites chosen for pilot study

Results These results are weekly

averages, NOT the 1-hr standard.

Baltimore and Albuquerque measured the largest NO2 values.

Baltimore also measured the largest background concentrations

The largest NO2 was collected at the rest area and the tollbooth

Rest area is a better location because tollbooth is influenced by background sources (port, tunnel, industry etc.).

Rest area may be influenced by idling trucks.

Results (cont.)

In general NO2 increases with AADT (and FE-AADT).

Circled outlier is tollbooth with possible background influences.

Outliers highlighted with square were influenced by roadway design.

Near road pilot study extension

We found slightly higher NO2 at the tollbooth site than at the rest area site. This is likely due to background sources.

Our plans are to locate a permanent monitor at the rest area site.

Rest area site

Tollbooth site

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Rest area site

Tollbooth site

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