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Hanover County air quality information - November 1, 2011 - 2:59 PM

Ozone Levels (measured in parts per billion)


November 1, 2011
1:00 AM - 3:00 PM		 1-hour average 8-hour average
1:00 AM - 2:00 AM 17 PPB 16 PPB
2:00 AM - 3:00 AM 14 PPB 16 PPB
3:00 AM - 4:00 AM 16 PPB **
4:00 AM - 5:00 AM 15 PPB **
5:00 AM - 6:00 AM 18 PPB **
6:00 AM - 7:00 AM 19 PPB **
7:00 AM - 8:00 AM 17 PPB **
8:00 AM - 9:00 AM **
9:00 AM - 10:00 AM **
10:00 AM - 11:00 AM **
11:00 AM - 12:00 PM **
12:00 PM - 1:00 PM **
1:00 PM - 2:00 PM **
2:00 PM - 3:00 PM **
Current 8-hour average 1-hour peak 8-hour average peak
** 19 PPB @ 6:00 AM 16 PPB @ 1:00 AM

(**) indicates that data is unavailable.


Air quality information from DEQ monitors is unofficial until quality-assured by the DEQ Office of Air Monitoring.

More on the Measurements

Because the Air Quality Index is calculated from past and current measurements, a single measurement does not correspond directly to a particular AQI. However, one measurement can predict what the final AQI level is likely to be. Here are some approximate ranges that can help you understand what these measurements mean.


Ozone (parts per billion)

1-hour 8-hour AQI Level
0-68 0-59 Green
69-86 60-75 Yellow
87-110 76-95 Orange
111-133 96-115 Red
134 and up 116 and up Purple

Eight-hour thresholds are lower because prolonged exposure increases the potential for health problems.

About Air Quality Measurements

This air quality information is collected from DEQ air monitoring stations across Virginia on an hourly basis. These stations measure the amount of ground-level ozone and particle pollution in the air at a specific time.

Not all stations monitor both types of air pollution. All available data for each station is displayed on that station's individual page.

Ground-level ozone is measured in parts per billion. A reading of 100 PPB means that 0.00001 percent of the air around the monitor is ozone gas. An average reading of 85 PPB over eight hours indicates an unhealthy level of ozone.

Particle pollution is measured in micrograms per cubic meter. A microgram is one millionth of a gram, or 0.000001 grams. The web pages for monitoring stations that have particle pollution monitors display only the particle pollution index (a value calculated from several hourly readings).