From Wikipedia:
Isoprene is produced and emitted by many species of
trees into the atmosphere (major producers are oaks, poplars, eucalyptus, and some legumes). The yearly production of isoprene emissions by vegetation is around 600 teragrams, with half that coming from tropical broadleaf trees and the remainder coming from shrubs.[1] This is about equivalent to methane emission into the atmosphere and accounts for ~1/3 of all hydrocarbons released into the atmosphere. After release, isoprene is converted by free radicals (like the hydroxyl (OH) radical) and to a lesser extent by ozone [2] into various species, such as aldehydes, hydroperoxides, organic nitrates, and epoxides, which mix into
water droplets and help create aerosols and haze.[3][4] While most in the field acknowledge that isoprene emission affects aerosol formation, whether isoprene increases or decreases aerosol formation is debated. A second major effect of isoprene on the atmosphere is that in presence of nitric oxides (NOx) it contributes to the formation of tropospheric (lower atmosphere) ozone, which is one of the leading air pollutants in many countries. Isoprene itself is normally not regarded as a pollutant, as it is one of the natural products from plants. Formation of tropospheric ozone is only possible in presence of high levels of NOx, which comes almost exclusively from industrial activities. In fact, isoprene can have the opposite effect and quench ozone formation under low levels of NOx.
By no means a scholarly article, but it sounds like Nitrous Oxide is the real problem, as Isoprene is naturally occuring and NOx is not (in the levels we see today) I think newsdaily.com (or whomever they stole the information from) is just looking to discredit biofuel production by coming up with a problem.
You might as well say water causes pollution because it is needed to create Methane!