Dehydroabietic acid (DHAA) is a specific organic tracer for the pyrolysis of conifer resin. To understand its atmospheric stability, the degradation behavior of particulate DHAA in the presence of hydroxyl radicals (OH) was investigated under different environmental conditions using a stainless steel reactor with volume of 30 cm³, in the dark. At 25 °C and 40% relative humidity (RH), the second-order rate constant (k₂) of pure DHAA with OH was measured to be 5.72 ± 0.87 × 10⁻¹² cm³ molecule⁻¹ s⁻¹. The influence of temperature, RH and mixing state on the degradation kinetics of DHAA were also investigated. At 40% RH, k₂ of pure DHAA increases with increasing temperature and follows the Arrhenius equation k₂ = (8.9 ± 1.9) × 10⁻¹⁰ exp[−(1508.2 ± 64.2)/T], while RH does not have significant impact on k₂ at 25 °C. At 25 °C and 40% RH, compared with pure DHAA, the corresponding k₂ for DHAA mixed with (NH₄)₂SO₄ decreased to 4.58 ± 0.95 × 10⁻¹² cm³ molecule⁻¹ s⁻¹, while the value was 3.30 ± 0.79 × 10⁻¹² cm³ molecule⁻¹ s⁻¹ when mixed with soot. The atmospheric lifetime of DHAA varied from 2.3 ± 0.2 to 4.4 ± 0.8 days under different environmental conditions. This study indicates that degradation of DHAA by OH radicals is appreciable, and a significant error in source apportionment should be introduced if the contribution of degradation to DHAA concentration is not considered during air mass aging.