ການພະຍາກອນຄຸນນະພາບອາກາດ
ຂໍ້ມູນຄຸນນະພາບອາກາດສະໜອງໃຫ້ໂດຍ: the Air Quality in Virginia (deq.virginia.gov) and Air Now - US EPA (airnow.gov)
Note that the measurements for NO2 (nitrogen dioxide) and CO (carbon monoxide) are taken from the station: Aurora Hills Visitor Center, Northern Virginia