Which meteorological parameter is included in ambient monitoring data only when available?

• A. Wind speed
• B. Precipitation
• C. Temperature
• D. Solar Radiation

Answer: (B)

Ambient monitoring networks gather weather information to help interpret pollutant measurements, and several meteorological parameters are routinely recorded whenever the sensors are installed. Temperature and wind speed are standard measurements that influence how air pollutants disperse and mix, while solar radiation is commonly tracked because it drives photochemical reactions affecting pollutant formation and breakdown. These are typically available across sites, so they show up in datasets whenever the station has the necessary instruments.

Precipitation, on the other hand, depends on having a rain gauge or equivalent equipment and data-sharing arrangements. Not every monitoring site maintains precipitation measurements, and some data streams include it only when precipitation actually occurs and the data are available. Because of this conditional availability, precipitation is the parameter included in ambient monitoring data only when it is available.