愿景2050系列视频（四）：重型卡车与公交车

Diesel exhaust is composed of fine particles that are a major contributor to global warming. To address this, 39 countries have implemented “soot-free” standards for new heavy-duty diesel engines that achieve better than a 95% reduction in black carbon emissions compared with older-technology diesel engines. Another option is to leapfrog to electric trucks and buses powered either by batteries or hydrogen fuel cells.