ການພະຍາກອນຄຸນນະພາບອາກາດ
ຂໍ້ມູນຄຸນນະພາບອາກາດສະໜອງໃຫ້ໂດຍ: the Air Quality in Virginia (deq.virginia.gov) and Air Now - US EPA (airnow.gov)
Note that the measurement for NO2 (nitrogen dioxide) are taken from the station: Long Park - Haymarket, Northern Virginia